1: /* dnsmasq is Copyright (c) 2000-2022 Simon Kelley
2:
3: This program is free software; you can redistribute it and/or modify
4: it under the terms of the GNU General Public License as published by
5: the Free Software Foundation; version 2 dated June, 1991, or
6: (at your option) version 3 dated 29 June, 2007.
7:
8: This program is distributed in the hope that it will be useful,
9: but WITHOUT ANY WARRANTY; without even the implied warranty of
10: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11: GNU General Public License for more details.
12:
13: You should have received a copy of the GNU General Public License
14: along with this program. If not, see <http://www.gnu.org/licenses/>.
15: */
16:
17: #include "dnsmasq.h"
18:
19:
20: static struct cond_domain *search_domain(struct in_addr addr, struct cond_domain *c);
21: static int match_domain(struct in_addr addr, struct cond_domain *c);
22: static struct cond_domain *search_domain6(struct in6_addr *addr, struct cond_domain *c);
23: static int match_domain6(struct in6_addr *addr, struct cond_domain *c);
24:
25: int is_name_synthetic(int flags, char *name, union all_addr *addr)
26: {
27: char *p;
28: struct cond_domain *c = NULL;
29: int prot = (flags & F_IPV6) ? AF_INET6 : AF_INET;
30:
31: for (c = daemon->synth_domains; c; c = c->next)
32: {
33: int found = 0;
34: char *tail, *pref;
35:
36: for (tail = name, pref = c->prefix; *tail != 0 && pref && *pref != 0; tail++, pref++)
37: {
38: unsigned int c1 = (unsigned char) *pref;
39: unsigned int c2 = (unsigned char) *tail;
40:
41: if (c1 >= 'A' && c1 <= 'Z')
42: c1 += 'a' - 'A';
43: if (c2 >= 'A' && c2 <= 'Z')
44: c2 += 'a' - 'A';
45:
46: if (c1 != c2)
47: break;
48: }
49:
50: if (pref && *pref != 0)
51: continue; /* prefix match fail */
52:
53: if (c->indexed)
54: {
55: for (p = tail; *p; p++)
56: {
57: char c = *p;
58:
59: if (c < '0' || c > '9')
60: break;
61: }
62:
63: if (*p != '.')
64: continue;
65:
66: *p = 0;
67:
68: if (hostname_isequal(c->domain, p+1))
69: {
70: if (prot == AF_INET)
71: {
72: unsigned int index = atoi(tail);
73:
74: if (!c->is6 &&
75: index <= ntohl(c->end.s_addr) - ntohl(c->start.s_addr))
76: {
77: addr->addr4.s_addr = htonl(ntohl(c->start.s_addr) + index);
78: found = 1;
79: }
80: }
81: else
82: {
83: u64 index = atoll(tail);
84:
85: if (c->is6 &&
86: index <= addr6part(&c->end6) - addr6part(&c->start6))
87: {
88: u64 start = addr6part(&c->start6);
89: addr->addr6 = c->start6;
90: setaddr6part(&addr->addr6, start + index);
91: found = 1;
92: }
93: }
94: }
95: }
96: else
97: {
98: /* NB, must not alter name if we return zero */
99: for (p = tail; *p; p++)
100: {
101: char c = *p;
102:
103: if ((c >='0' && c <= '9') || c == '-')
104: continue;
105:
106: if (prot == AF_INET6 && ((c >='A' && c <= 'F') || (c >='a' && c <= 'f')))
107: continue;
108:
109: break;
110: }
111:
112: if (*p != '.')
113: continue;
114:
115: *p = 0;
116:
117: if (prot == AF_INET6 && strstr(tail, "--ffff-") == tail)
118: {
119: /* special hack for v4-mapped. */
120: memcpy(tail, "::ffff:", 7);
121: for (p = tail + 7; *p; p++)
122: if (*p == '-')
123: *p = '.';
124: }
125: else
126: {
127: /* swap . or : for - */
128: for (p = tail; *p; p++)
129: if (*p == '-')
130: {
131: if (prot == AF_INET)
132: *p = '.';
133: else
134: *p = ':';
135: }
136: }
137:
138: if (hostname_isequal(c->domain, p+1) && inet_pton(prot, tail, addr))
139: found = (prot == AF_INET) ? match_domain(addr->addr4, c) : match_domain6(&addr->addr6, c);
140: }
141:
142: /* restore name */
143: for (p = tail; *p; p++)
144: if (*p == '.' || *p == ':')
145: *p = '-';
146:
147: *p = '.';
148:
149:
150: if (found)
151: return 1;
152: }
153:
154: return 0;
155: }
156:
157:
158: int is_rev_synth(int flag, union all_addr *addr, char *name)
159: {
160: struct cond_domain *c;
161:
162: if (flag & F_IPV4 && (c = search_domain(addr->addr4, daemon->synth_domains)))
163: {
164: char *p;
165:
166: *name = 0;
167: if (c->indexed)
168: {
169: unsigned int index = ntohl(addr->addr4.s_addr) - ntohl(c->start.s_addr);
170: snprintf(name, MAXDNAME, "%s%u", c->prefix ? c->prefix : "", index);
171: }
172: else
173: {
174: if (c->prefix)
175: strncpy(name, c->prefix, MAXDNAME - ADDRSTRLEN);
176:
177: inet_ntop(AF_INET, &addr->addr4, name + strlen(name), ADDRSTRLEN);
178: for (p = name; *p; p++)
179: if (*p == '.')
180: *p = '-';
181: }
182:
183: strncat(name, ".", MAXDNAME);
184: strncat(name, c->domain, MAXDNAME);
185:
186: return 1;
187: }
188:
189: if ((flag & F_IPV6) && (c = search_domain6(&addr->addr6, daemon->synth_domains)))
190: {
191: char *p;
192:
193: *name = 0;
194: if (c->indexed)
195: {
196: u64 index = addr6part(&addr->addr6) - addr6part(&c->start6);
197: snprintf(name, MAXDNAME, "%s%llu", c->prefix ? c->prefix : "", index);
198: }
199: else
200: {
201: if (c->prefix)
202: strncpy(name, c->prefix, MAXDNAME - ADDRSTRLEN);
203:
204: inet_ntop(AF_INET6, &addr->addr6, name + strlen(name), ADDRSTRLEN);
205:
206: /* IPv6 presentation address can start with ":", but valid domain names
207: cannot start with "-" so prepend a zero in that case. */
208: if (!c->prefix && *name == ':')
209: {
210: *name = '0';
211: inet_ntop(AF_INET6, &addr->addr6, name+1, ADDRSTRLEN);
212: }
213:
214: /* V4-mapped have periods.... */
215: for (p = name; *p; p++)
216: if (*p == ':' || *p == '.')
217: *p = '-';
218:
219: }
220:
221: strncat(name, ".", MAXDNAME);
222: strncat(name, c->domain, MAXDNAME);
223:
224: return 1;
225: }
226:
227: return 0;
228: }
229:
230:
231: static int match_domain(struct in_addr addr, struct cond_domain *c)
232: {
233: if (c->interface)
234: {
235: struct addrlist *al;
236: for (al = c->al; al; al = al->next)
237: if (!(al->flags & ADDRLIST_IPV6) &&
238: is_same_net_prefix(addr, al->addr.addr4, al->prefixlen))
239: return 1;
240: }
241: else if (!c->is6 &&
242: ntohl(addr.s_addr) >= ntohl(c->start.s_addr) &&
243: ntohl(addr.s_addr) <= ntohl(c->end.s_addr))
244: return 1;
245:
246: return 0;
247: }
248:
249: static struct cond_domain *search_domain(struct in_addr addr, struct cond_domain *c)
250: {
251: for (; c; c = c->next)
252: if (match_domain(addr, c))
253: return c;
254:
255: return NULL;
256: }
257:
258: char *get_domain(struct in_addr addr)
259: {
260: struct cond_domain *c;
261:
262: if ((c = search_domain(addr, daemon->cond_domain)))
263: return c->domain;
264:
265: return daemon->domain_suffix;
266: }
267:
268: static int match_domain6(struct in6_addr *addr, struct cond_domain *c)
269: {
270:
271: /* subnet from interface address. */
272: if (c->interface)
273: {
274: struct addrlist *al;
275: for (al = c->al; al; al = al->next)
276: if (al->flags & ADDRLIST_IPV6 &&
277: is_same_net6(addr, &al->addr.addr6, al->prefixlen))
278: return 1;
279: }
280: else if (c->is6)
281: {
282: if (c->prefixlen >= 64)
283: {
284: u64 addrpart = addr6part(addr);
285: if (is_same_net6(addr, &c->start6, 64) &&
286: addrpart >= addr6part(&c->start6) &&
287: addrpart <= addr6part(&c->end6))
288: return 1;
289: }
290: else if (is_same_net6(addr, &c->start6, c->prefixlen))
291: return 1;
292: }
293:
294: return 0;
295: }
296:
297: static struct cond_domain *search_domain6(struct in6_addr *addr, struct cond_domain *c)
298: {
299: for (; c; c = c->next)
300: if (match_domain6(addr, c))
301: return c;
302:
303: return NULL;
304: }
305:
306: char *get_domain6(struct in6_addr *addr)
307: {
308: struct cond_domain *c;
309:
310: if (addr && (c = search_domain6(addr, daemon->cond_domain)))
311: return c->domain;
312:
313: return daemon->domain_suffix;
314: }
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